1. Field of the Invention
Aniline and alkyl anilines are obtained by the reaction of anhydrous ammonia with cyclohexane or cyclohexane having up to two lower alkyl substituents at elevated temperatures, such as 300.degree.-650.degree. C, in the presence of selected catalysts, such as zinc oxide alone or with vanadium, molybdenum or titanium oxides, etc.; metal compounds such as vanadates, molybdates and titanates; and cadmium sulfide, zinc selenide and the like. The presence of water in this reaction is beneficial in increasing the amount of aniline produced, or in reducing the amount of undesired by-products, or both.
2. Prior Art
Aniline has been prepared heretofore by reduction of nitrobenzene or by ammonolysis of chlorobenzene. Other methods of producing aniline are also known. For example, a noncatalytic method reacts cyclohexane, ammonia and sulfur, as shown in Canadian Pat. No. 815,064.
A catalytic method is shown in Bloch, U.S. Pat. No. 2,980,735 where an alkylcyclopentene is heated in the presence of cobalt metal or nickel metal. Oxides of metals of Group V, VI and VII are disclosed as possible components of the catalyst.
Another method is that shown in British patent 1,327,493 which discloses the heating of an aromatic compound such as benzene with ammonia in the presence of water and a nickel/nickel oxide catalyst.
In pending application U.S. Ser. No. 687,175 filed May 17, 1976, a continuation-in-part of U.S. Ser. No. 536,584, filed Dec. 26, 1974, now abandoned, which was a continuation-in-part of U.S. Ser. No. 445,914, filed Feb. 26, 1974, now abandoned, there is disclosed the reaction of catalytically reacting cyclohexane and ammonia to produce aniline, but in the absence of water. It has now been found that when this reaction is carried out in the presence of a designated amount of water, benefits are obtained, as for example, increasing the amount of aniline produced, or reducing the amount of undesired by-products, or both.